A bypass/flushing valve for a hydrostatic system includes a valve body including a central bore, a shuttle valve located in the central bore, and a valve spindle disposed within the central bore. The valve body includes four ports each in communication with the central bore. The shuttle valve blocks flow through the central bore between a first port and a second port. When pressure at the second port is higher than at the first port, the shuttle valve moves to allow flow passage between the first port and the third port. When pressure at the first port is higher than at the second port, the shuttle valve moves to allow flow passages between the second port and a third port. The spindle is movable between a first position to block communication between the second port and the fourth port and a second position to allow for communication between the second port and the fourth port.